Influence of impurity iron ions on nonlinear coloration of alkali-silicate glasses

Abstract

A study was made of the role of iron impurity ions in the formation and decay of colour centres in alkali-silicate glasses in the course of multiphoton absorption of laser radiation. An increase in the concentration of Fe2O3 enhanced the residual absorption by stable hole colour centres and reduced considerably the lifetime of unstable electron colour centres. Repeated irradiation of glasses containing a small amount of the impurity increased the residual absorption, whereas the induced absorption (measured immediately after the action of a radiation pulse) did not change from one pulse to the next and was governed solely by the radiation power density. An increase in the Fe2O3 concentration destroyed this effect.